The present invention is directed to flying spot scanners (commonly referred to as raster output scanners (ROSs)) which typically have a reflective multifaceted polygon mirror that is rotated about its central axis to repeatedly sweep one or more intensity modulated beams of light across a photosensitive recording medium in a line (fast) scanning direction. While the beams sweep across the photosensitive recording medium, it is advanced in an orthogonal, or "process", direction, commonly referred to as the slow-scan direction, such that the beams scan the recording medium in accordance with a raster scanning pattern. Digital printing is performed by serially modulating the intensity of each of the beams in accordance with a binary sample stream, whereby the recording medium is exposed to the image represented by the samples as it is being scanned.
Printers that sweep several beams simultaneously are referred to as multibeam or multispot printers. Moreover, dual or multispot lasers are considered to be an enabling technology for high speed printers operating at resolutions of about 600 spots per inch (spi) while producing output at greater than 80 pages per minute (ppm). Monolithic laser arrays, while providing the multispot capability, have typically been strongly sensitive to thermal crosstalk when used in closely spaced lasers having interbeam spacings of less than 250 .mu.m, and are not easily adapted to provide multiple wavelength and/or multiple polarity laser beams.
The following disclosures relate to both ROS printing devices and multibeam laser diodes which may be relevant: